Description Of The Business And Summary Of Significant Accounting Policies Description Of The Business And Summary Of Significant Accounting Policies (Reconciliation Of Net Income Attributable To Ensco Shares Used In Basic And Diluted EPS Computations) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Description Of The Business And Summary Of Significant Accounting Policies [Abstract]
Income (Loss) from Continuing Operations Attributable to Parent	$ (1,466.1)	$ (2,703.1)	$ 1,421.6
Other Preferred Stock Dividends and Adjustments	2.0	7.9	15.1
Income (Loss) from Continuing Operations Attributable to Parent, Available to Common Stockholders	$ (1,468.1)	$ (2,711.0)	$ 1,406.5

Description Of The Business And Summary Of Significant Accounting Policies Description Of The Business And Summary Of Significant Accounting Policies (Reconciliation Of Net Income Attributable To Ensco Shares Used In Basic And Diluted EPS Computations) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Description Of The Business And Summary Of Significant Accounting Policies [Abstract]

Income (Loss) from Continuing Operations Attributable to Parent

$ (1,466.1)

$ (2,703.1)

$ 1,421.6

Other Preferred Stock Dividends and Adjustments

2.0

7.9

15.1

Income (Loss) from Continuing Operations Attributable to Parent, Available to Common Stockholders

$ (1,468.1)

$ (2,711.0)

$ 1,406.5